Telephone system



July 24; 192s; -Lsvsne Y L. A. MORTIMER TELEPHONE SYSTEM Filed June 2, 1927 /N i 0a/5 A Mmm/m l O, Arm/mfr Patented July 24, *1928.

il UNWED STA PATENT voFFlcE.

nons encamina, or" Honorine, viiLssieyno,It"tifoistinti TELEPIONE LABORATORIES, INCORPORATED, or NEW Yonx, n. 1A ooRroA'rIon 'oF NEW YORK,

Application ined :rime 2,

This invention relates to telephone systems and particularly `fto` means whereby signaling current may be automatically applied to a seized linev for a single periodof pre-` determinedlength. f

In accordance with a feature, of thisfin- Vention a series oftimingrelaysunder control "a ti'niing interrup'ter are common to a pl'naIityof trunks and may be4 exclusively appropriated `fory adelin'ite interval'by one or simultaneously by rsew'ier'al trunks Other trnnlis 'attemptiiigtoj use this common equip; nient 'dni-ing 'siicli period are barred'and inns't await thefbegnning "of a new timing period. j

VIn accordance With'another feature of the invention means `forapplying signaling current to a connected t'rnnl line `for asingle period oit predetermined length is madecomnien to th'eincoining sends" of connecting trimls 'whereby 4the ainonnt*I of eXpensive timing apparatus heretofore made individual vto the ontgoi endsydfithe connected ktrunks isreduced',toalininininm;

rlhe drawings coinprise a `d iagrammatic representation' of the incoming' end "of `a straightforward trunkand the dntgoing end of a 'toll linejorer which` a telephonie connection may be established". Theupljier part or the, enfawingjshews the neonnng end of a straiglitoriyard Itriinl; circuit vrep'resentative ol. a group off such trii-nks" and the outgoing end "o'i". a` 'tollplinefalso represeiiftativeo a gron'p. In the loiver partothe drawing 'apparatus common v,to the incomiiigftrunlis ionez'cirouiatheo y the ringing currenty timing"circuit` c f ln'geneial,they operation is as follows: A distant j operator` seizes vthestra'ightfor- \ya1(1l`tr`u`1`ik anlfthe trnl lamp `10 there- 'npon'flaslies The B operator (then fli'stens inv/by `operatiifng the individual trniil liey'fll. inthe` process of connecting `the opeiato's telephone `set to thetriinlr, a sigpferators telephone set and y nal consisting of three successive momentary s @Em-:Paone sys'fffm issignalled by single application of a ringing current for a period of predetermined dnraivional Drie to the! fact that toll lines are generally long and employ composite ringers heievge'knerailly indicated' by the 'box designated r'50,1 the l application lof ringing current minst be" maintained `for an appreciable time, "for enfalnple,itwo seconds. When the conL nectio extendedto t`he toll" line certain apparatus common to the incoming end' of igh'e:straightforward trunk`J` ifjit is not in use aft that instant; is'iappropriated andl acts .to transmit la'sgnal over t'he ltoll line. `Also vinfr?responsel to the extension of the connes tion tothe toll* line, operators telephone set is automaticallydisconnected, the tru-nk lamp becomes dark and tlresupervilsory :signal tliedistantAl oprators position is actuated. At tlee'ndl of the conversation,"

When the distant A operator disconnects from' the trunk, lthe Ltruvnlrvlamp lights stead'- ifl yf. Ylli-the distant Ajl 4operator"ag-'fain seizes "the trunk Vbefore the cl? "operator has taken `the connection down the itrunk ylamp' flashes and the B operator Will have to take'down `tlie oldcnnection before `she can act to establish a new one;y

Th'ealooye"operations detail will now be f,

described:ly V i A Au coniietion ifs extendedfover the fistraifghtyforrvardfjt'rii'nk line shown in the drawings 'by-connecting battery and' 'ground to cond'rictors'*l nd 2 fof the trunk in any Wel-l known mai ner,` Wherepon current'k will flow eter thesc'ondnctors; the left'hand' windings otr repeating coil' 'Sjalnd` the upper low resistance" and floiverjhi'ghs resistance windings of itn'ie idd establishes fan?. obvious circuit :for 'relay' a3 liieil'ay 4 attracts its'fa'rmatures and efftendsa connection from battery, interrnpterl, relay T, conductor 8front' Contact `and lefthand "armature 'ot relay LLj'left hand armature and backfcontact of relay E9, signal lhnp"10i-towgronnd.` Lamp lO flashes in nii'iso'n `Witli 'the' operation of interrupter 6. Reli ,7 operates inthiscircuitandapplies gronndto one terminal of pilot lamp 12. "f lh'e'` other terminal 'of pilot lamp 12 extends thronglr resistance 11", baclfcontaet and inner right land'armature of Erelay 9, front contact 5and,righthand armature ofiirela'y Li toibattery and ground' sothat` lampl 12 lashes in n-"iiisoii with individual'lamp .10. The opera tor' at this position `as soon; es she f is free to series through the normal contacts of all intermediate trunk keys such as 14 and the normal contacts of. thel last trunk key 16 to theconductor 17. Upon depression of key 14, ground is extended over this chain -cir. cuitas far as key 14 and thence through the alternate contacts of key 14, Windingfof re" I' lay 15, back vcontactandv inner right hand armature of relay 9, 'front contact and right hand varmature of relay 4,y to battery andA ground. Relay 15 becomes energized in 'this' circuit and when key 14 is returnedltonorinalslocks in a circuit ncludingthe chain contacts of the listening keys', conductor 17, iront contact .and inner upper armature of relay 15',.winding of relay`15, back contact andy inner right hand armature of lrelay 9, front contactand righthand armature of relay 4 to battery. f' It will 4benoted `that relay 15 Will remain energized in this circuit until the chain circuitthrough the listening keys is disturbed as when' for instance some other listening key is actuated or when relay 9 is operated upon the .insertion of' plug 31 injack 32, whereupon the looking circuit for relay15 is opened.

Upon the :operation or' relay 15, conductors 18 and 19 are connected to the righty handr windings of lrepeating coil 5 vso that the operators set Which will be shortly connected to these conductors Willbe yassociated with the trunk circuit. U on they operation of relay 15 ground on con uct or"17..SL1pplied over the chain ciicuit 4above described is eX- ended through the front contact and inner lower -armature of rela-y 15, conductor 20, normal contacts of the right handr armature of relay 21, Winding of relay 22 to battery. Relay 22 becoming energized completes a circuit from ground, primary of induction coil 23', front contact and left hand armature of relay 22, normal contacts of left hand armature of relay 24, normal contactsof the left'hand armature of relay 25, interrupter 26 to battery and ground. The interrupted current flowing through the primary of induction coil 23 causes a tone. toibe induced in the secondary Winding thereof Which4 being connected throughthe back contacts of the outer right and left hand armaturesof relay 27 to the conductors 18 and 19 causes a tone to be transmitted back over the'trunk. Relay 22 in energizing closesia kcircuit from ground, iront contact andright hand armaturek ot relay 22, Winding of relay 24 to battery, whereupon relay 24 becomes energized and opens the circuit for interrupter 26 so that the tone transmitted'back over f the trunk is now cut on?. Relay 24 also eX- tends the ground which was used for its lenergizationover its front contactand right hand armature to the Winding of relay 28. Relay 28. establishes a circuit roinground, thepriniaryof induction coil 23,'front contact `and lefthand., armature of `relay, 22, front Contact and left hand armature of re klay,24,`left hand armature and front contact of relay 28, normal contacts of the left hand armatureofrelay L25` to vinterrupter 26 so that tone isr againf transmitted back over the trunk. y Y' `Upon the y,ene'rgization of, relay 28 a circuit is established,romground, front contact and `right ,hand armature of relay 22, i

' whereupon alcircuit is established;v from ground,primary of induction coil 23 front contact vand lefthand armature ofrelay 22, front contact and left hand` arinatureof relay 24,'v left hand armature and front convtact ot relay .28, front contact and `left hand armature of Arelayvv25, left hand armature and front contact Vorelay 29,1.to interrupter 26 so ythat tone is now fora third vtime transmitted back` oyer the trunk. Relay 29y in energizing lalso closes yan obvious circuit for the energizationfof relay 21.. yRelay 21 in energizing .extends a connection from ground,lfront Contact and right hand armature of yrela-y ,29, left hand armature Land yfrontcontact of relay 21,v front contact'and ,right handarmatureqof relay 21, to the Winding of relay 27 .whereupon the secondary circuit of induction coil 23 is openedy and the tone is'for the last time cut off from ,c the trunk. Relay 21 becomes lockedin a yleft hand `armature of relay 21, Winding of relay 21 `to battery.

Upon ,the energizations of relay v21,*thek original circuit 'for Vrelay 22 is openedr and thereupon in turn relays 22, 24, 28. 25`and 29 become deenergized leaving relays 21 and p 27 in their energizedy conditions. Thisfcondition Will be maintained until'relay 15 becomes deenergized.

Upon the operation ofrelay 27, *thev opera- 'y tors' telephone isl connected to conductors 18 and 19 and she may-'communicate with" Vthe distant operator by means rof repeating coil 5y and` trunk conductors 1 and In-v formation Will 'now be passed'to the operaset' Vrh-ich4 will result in terror" the ,farther -xtfsin or the donnee: tion; Assiirhingflthattlieonneetin ijst''b xijendediokfr reunite' l30 the" opmter may menthe ripnf prag 31 t the Sieveofjack a contlitinis' encountered it vwill causen f lfoy ofcurre'ut oye'r lthetp"ofplug 31, ltlie upper outer armature ancl back el tact of relay 33, the upper outer armatlijire tothe 'busy `test Avif'iiidiiig of the induction coi 'associated with theperators telephone thevortlinary busy test indieationl y :Assuming that the `toll line` isfound' to be idle' ftlie 'operator' will insertplug 31 into jack therebyestablishing 'a `circuit from ground, sleeye of jack 32 ancl'sl'eeve of "plug 31, Winding ol 'relay 35-` a'dftyiicliiig of *reklay '36 tobatte'ry. Bo'ththese relays become energizecl. Relay 35 closes an efbyiiis' circuit for. the erergizatioii of relay 9` whereupon the" holclfingcirenit of lelay'l' is opened and this elayfreturns Vto normal thereby diseom ne'ting the op'eatos telephone set frein the rrunkigAt une sans time the @nella for laniij 10 isa 'opnetl afntl'fthis' lainpbecoines ilarl. 'Shree/'lmnp 10 is in Iseries With relay 7,-relay'7 nonf'ceasestfo operate and pilot lamp '12 b'eeomes Clark" j Relay se niet@ n n; tand armature. 'andI vront' Contact *short circuits the .flower hier ,resistente waning@ relay e; uns

f causing an' inereas''ir cur-rent inl @endurer-s hand arinaturefof relay 87, Wintlin gjof" v rela'y nattl contacts" of fits inner 'upper armature. Relay 33; in 'operating `impresses'r'ingjfirg; 'current on' the' truirlr aritllc'aufses" the compositi-3 ringer here designated by the numeral 50 to functies ln When i'nerrupter `4()'2r.' e`acl`1es`aefiyeri posinon einer@ theiriiijt isiclei'therethrough, groiintl Wlflbe entendetlwover coduetor'4l, the" outer rightv` har a'llnatu'i-and" front Contact of `relay 19, the back conta'etland `'left hand" armature of rialy e7; Conductor 4e, left hand' 'arrnadufleand"baelreonta'ct' 'o'f re rlay 39, yiin'dingff relay" 43tobatteryQRelay 43 becomes energized-anu establishes a eonnecton from ground, the normal contacts of the armature oflelay 44, armature' yand front 'contact-jef relay 43," Winding of' relay 39, but thisici'reiiit is vinelectiye" laslong as interrupter 40"maintaieisV a" Closed' eireuit.

'Tf relay 39 is not"at' this When y,interrupter 4G new opens its circuit relay 39 Willbeeoine energized and relay 43 Will reniain energized over the^circuit just described.' After a preiletermined period interrupter 4() will again close the circuit t0 conductor 41 so that ground is nbwexten'ded oyer the-left hand arnfiaturey and frontfcontactjo'l' relay 39, VWinding of relay 45 tobattery. Relay be'coines energized and closes a circuit from ground, left hand `armature and front Contact of relay 45, Winding" ,of relay 44, inner right hand armature and front contactot relay 39 to the Windingn of relay 45,4 but this circuit is neffeetivefto cause the energization of relay 44 so long as interru'pter 40 maintains aground connection on conductor 41. As soon as interrupter 40 opens theicircuit ,to Conductor 41,2relay 44 becomesenergized iirseries with relay 45 and relay 45remains energized. tiorrolfrelay 44 closes a lcircuit from groun, 'front eontactancl arnature of relay 44, con'- (lueter 46, front. contact andA inner lower armatureezf relay 33, Winding of relay' 371to battery. Relay `37 becominfenergized locks to the `ground supplietl by the rightihand ar? nurture ofrelay 36 anrl'iope'ns the holding circuit of relay '33 `so that relay 'fnowreleases and cuts off ringing currentfroin the The energiza.n

toll line 30.1 Atv the saine timezrelay 37 195 opens theconnecion to conductor 42 so ythat th'ewiinpulses set up by1nterrupter 40 Will non'y no longer be effective Ato operate.they timing relays.' Relay 44 `in opcrating'also Opens thecireuitfo relays 39^anclf43 and? these relays return' to normal. Relay 39 be` ing slow to release maintains the circuit for the energizat-ion of relays 44- and 454er a shertpwerid: after which these relays return tonorrnal. w `j' At theenclofthe conversation the distant oprator breaks lthe connection to conductors 1 and' 2 and" relay 3 and i in turny relay 4 beconnesdeenergized;` A circuit is thereupon established1A from ground," right hand arma ture 'and' back Contact of relay 4, Winding of relay47,` front Contact and arinature of yrelay 35 to ground'.v A circuit ni'ay new be tra'ceel froml battery, the lifniclelle right hand armature and front Contact of `relay 47, back Contact andfileft handarinature ofrelay 4, front Contact anclfinner left hand armature ofl yrelay47,signal lanip 10 to ground so that lampi() new glows steadily to indicate to the operator having` Vcharge .of [this trunk that the connection may bebroken.` Relay 47 alsolocks up `through its inner "right hantl'iarinature and front/Contact so lthat :if

the distant operatorfshould again seize the trunkA and; Cause .the energization of relays` 3 :12

`ruiliiter 6, relay 7 conductor 8,-front contact andlet hantlarmatine 'et relay 4, front contact and inner left hand armature of relay 47 to lamp l() so that, lampi() will again flash as When the trunkWas iirst seized. This Will act as a calling signal so that the operator Will remove plug 31 from jack 32 and proceed to establish a new connection in the manner her-einbefore described.

Under ordinary conditions when lamp 10 glows steadily the operator ivill remove plug 31 from jack 32 Which Will result in the inimediate restoration to normal of relays 35, 36, 37 and relay 9.

It Will be noted that the ringing relay v33 can only be energized When relay 39 is iii its normal position and hence the period during Which relay 33 may remain energized is definitely measured by the operation of interrupter 40 so that ringing current from source 48 Will be applied to the tip and ring conductors of plug 3l and jack 32 to cause the operation of the composite ringer U50, for a definite and predetermined period of time. It Will be further notedtliat tlie cir,- cuit Jfor relay 3-3inay be prepared during the operation of the train of timing relays. It may happen that several such relays 33 are prepared for operation and hence when relay 39 becomes deenergized each otthese` relays 33 will become operated and hence ringing current Will be applied to 'several corresponding trunks simultaneously. Other relays y33 which may be prepared for operation during this period may not be operated until this ringing period has ceased and a new ringing period as determinedby the operation of interrupter 4() has been initiated.v i f What is claimed is: r

1. In a telephone system, a link circuit, a trunk line, means .for connecting said link circuit to said trunk line and means common to said linkcircuit responsive'to the establishment of said connection for impressing 'signaling current on said trunk lineifor a rangement common toA said link circuit responsive to thel establishment ot said connection for impressing the signaling current on said trunk line for a single period of predetermined duration. v

4. `In a telephone system, a link circuit, a trunk line, means for connecting said link circuit to said trunk line, means common ,to

said link 1 circuit for impressing signaling current on said trunk line for a single period of predetermined duration, means responsive n to the establishmentof said connectionpfor causing said common means to operate and means responsive to the busy condition oif said common means yfor delaying its opera-` tion.:y ,t l

5. In a telephone system, a link circuit, a

trunk line, means for connecting said link f circuit to said trunk line, a `ringing relay individual to said link circuiti'or impress ing ringing current on said trunk line, means common to said link circuit orcaus-` ing said individual vrelay to operatev for a single period of predetermined duration and means responsive to the establishment of said connectionoi1 said link'circuitto said said common means means common to ysaid link circuit yfor causingsaid individual relay to operate for a singleperiod of predetermined duration, means rresponsive to-fthe establishment of ksaid connection of saidjlinkcircuit to ysaid ytrunk line for settingsaid common means ,into operation and means responsive to the busy conditiony ofsaid common means fordelaying the operation of said individual relay.

7. Ina telephone system, a pluralityy of linky circuits, a trunk-line, meansfor connecting any one-of said link circuits to'v saidy trunk line,a ringing relay indivi-dual to each of said'link circuitsfor impressingy ringingcurrent on lsaidwtrunk line,y means commento 'said link circuit for causing said individual' relay Ito. operatey for 'a single period i of predetermined duration, means Aresponsive to fthe establishment of a. connection between :any one -ofwsaid link circuits and `said trunk line orpreparing forl the op,-

eration of a corresponding individual relay and ymeans responsive toj the idleV condition of ysaidl commonvmeans andl tosaid last means for operatingsaid individual relay.

8. In a telephone system, a plurality of link circuits, a. plurality ottrunk. lines,

:means for connecting any/one of said link circuits to any one of said trunk lines, a

.ringing relay lindividual, to each of said link'circuits -Vfor impressing ringing current on a connected trunk'line, meanscommon to saidlink circuitsfor-causing said individual relays to operate `for a 'singleperiod of a predetermined; duration, an venergizing cirvcuit for eachl of said individual relays,-means responsive tothe establishment of a connection betvveena link circuit and a `trunk lline for preparing a, corresponding, energizing ,circuit for operation, andmeans responsive los to the idle condition of said common means vand to the preparation ofone of said enerlink circuits for causing said individualk relays to operate for a single period of predetermined duration, an energizing circuit for each of said individual relays, means re sponsive to the establishment of a connection between a link circuit and a trunk line 'for preparing a corresponding energizing circuit for operation and means responsive to the idle condition of said common means and to the simultaneous preparation oi a plurality of said energizing circuits for operating a corresponding plurality of said individual relays. y

' 10.` In a telephone system, a plurality of link dircuits, a plurality of trunk lines,

means for connecting any one of said link circuits to any "one 'of said trunk lines, a relay individual to each of said-link circuits for `impressing ringing current on a connected trunk line, means common to said link circuits for causing said individual relays to operate vfor al single periodof predeter` mined duration, an energizing circuit for eacliof said individual relays, means res ponsive to the establishment of a connection between a link circuit and a trunklinev for preparing the corresponding energizing circuit `for operation, means responsive to the idle condition of said common meansand to the preparation of one of said energizing circuits for operating a corresponding one of said individual relays and means responsive to the preparation `of other of said energizing circuits lduring the operation of said individual relay for delaying the operation of the corresponding other of said individual relays.

In witness whereof, I hereunto subscribe my namel this lsty day of June, A. D. 1927.

- LGUIS A. MORTIMER. 

